ISTANBUL, Turkey -- Turkish police detained more than 40 people in four provinces early Friday over alleged links to a Kurdish terror organization, authorities said.

As police extended their search in Istanbul and other areas for Kurdistan Workers' Party, or PKK, suspects, a provincial chairman of the pro-Kurdish Democratic Society Party, or DTP, was arrested after condemning the investigation, the Hurriyet Daily News reported.

The private Dogan News Agency said 21 people were held in operations carried out in the western province of Izmir, accused of arson, as well as several bomb attacks.

Police also searched DTP quarters in the central district of Beyoglu, Istanbul and in the southeastern province of Batman, where 15 people were detained.

The PKK is listed as a terrorist group by Turkey and much of the international community, including the United States and the European Union.